Like a Breath of Fresh Air – Only Thinner

2020-05-04 12:47:37.000 – AJ Grimes, Weather Observer


Here at the Observatory, we get a lot of questions regarding altitude and the lack of oxygen on the summit. I thought we could continue last week’s theme of high altitude, but instead of baking tips, this week we will investigate the effects on the body as one ascends through the atmosphere and the changes it automatically makes to adjust. Since the air is thinner at the height of Mount Washington (6,288 feet), less oxygen is available with each breath – about 20% less than at sea level. In order to meet your body’s oxygen demands, it must make some changes to continue to get what it needs.


A breathtaking morning view from the summit.

If you were to climb to the summit of Mount Washington, you might notice the lesser oxygen content by getting “winded” more quickly. This means your oxygen demand is harder to meet with less oxygen coming in with each breath. You would compensate immediately by increasing the volume and frequency of breathing by taking deeper breaths and breathing faster. Your body makes short-term accommodations like these when you do any aerobic exercise. The problem is that doing this over a long period of time takes a lot of energy, so this mechanism really acts like a bridge while your body does some other things to acclimate to the altitude.

Red blood cells carry oxygen from your lungs out to your body, and carbon dioxide from your body back to the lungs. So, more red blood cells means more carrying capacity. To make this happen, your body produces a signaling protein called erythropoietin, which stimulates the production of red blood cells. The more red blood cells available to circulate oxygen and carbon dioxide, the more effective each breath is. The body also makes each red blood cell more efficient by creating a molecule called 2,3-DPG. This molecule is in red blood cells and changes how their hemoglobin binds oxygen. You want the red blood cells to pick up oxygen where there is a lot of it (in the lungs) and drop off oxygen where there is little of it (at the tissues). In order to do that, hemoglobin must let go of oxygen more readily at the tissues. Even with less oxygen available in the lungs, there is still enough for this mechanism to ensure that red blood cells pick up enough oxygen in the lungs, but also that the 2,3-DPG makes them dump more oxygen in the tissues. Other factors can affect oxygen delivery similarly – for instance, lactic acid from anaerobic exercise like weight lifting, and increased temperature.

In spite of these changes, don’t worry – Mount Washington is a tall mountain, but not tall enough to reach the altitude where people can no longer acclimate, called the “death zone”. This altitude is generally considered to be around 26,000 feet above sea level, where peaks such as Mount Everest and K2 reach. However, if you climb Mount Washington or do any sort of work up here (such as climbing up and down stairs and ladders to de-ice instruments), you will notice a difference in how your body reacts to the altitude!


AJ Grimes, Weather Observer

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